Before
the 1970's, virtually nothing was known about orca social structure.
As a result of the pioneering photo identification study undertaken
by Dr. Michael Bigg of the Pacific Biological Station at Nanaimo which
began in 1972, each of the individual orcas found along the coasts
of British Columbia and Washington State was identified and assigned
an alphanumerical identification ("ID"). It became apparent to Dr.
Bigg and his associates that the orca population was not as large
as first assumed. Individuals live in small stable family units within
a larger community. Since then, our understanding of the resident
orca social structure has continued to be refined and at present is
described in the following manner: